Comparative efficacy of repetitive transcranial magnetic stimulation protocols for obsessive-compulsive disorder: A network meta-analysis.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) has been found to be helpful for the treatment of obsessive-compulsive disorder (OCD). However, the relative efficacy of different rTMS protocols is unclear. OBJECTIVE: To conduct a systematic review and network meta-analysis (NMA) of published literature to compare the relative efficacy of different rTMS protocols for decreasing Yale-Brown Obsessive Compulsive Severity (Y-BOCS) scores in patients with OCD. METHOD: Relevant articles published between 1985 to September 2023 were searched from the Cochrane Central Register of Controlled Trials, PubMed and PsycInfo. Double or single-blinded randomized controlled studies conducted on patients with OCD comparing an active rTMS protocol with either another active or sham rTMS protocol were included. Network meta-analysis (NMA) was conducted using a frequentist approach. Standardized mean difference (SMD) of change in Y-BOCS scores was calculated employing Hedge's g. Pairwise meta-analysis using random effects model was conducted which was extended to the NMA using restricted maximum likelihood estimation procedure. Surface under the cumulative ranking (SUCRA) probabilities were used to rank the interventions. RESULTS: Excitatory rTMS of the bilateral dorsolateral prefrontal cortex (DLPFC), inhibitory rTMS of right DLPFC, inhibitory as well as excitatory rTMS of bilateral medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC) and inhibitory rTMS of bilateral supplementary motor area (SMA) were superior to sham stimulation. The DLPFC and mPFC/ACC protocols had a higher probability of being among the top-ranked interventions. The majority of studies had a modest sample size and at least some concerns in the risk of bias assessment. CONCLUSION: rTMS targeting either the medial or lateral prefrontal cortices is a promising intervention for resistant OCD. There is a need to confirm these findings in large systematic studies.

Global multi-center and multi-modal magnetic resonance imaging study of obsessive-compulsive disorder: Harmonization and monitoring of protocols in healthy volunteers and phantoms.

OBJECTIVES: We describe the harmonized MRI acquisition and quality assessment of an ongoing global OCD study, with the aim to translate representative, well-powered neuroimaging findings in neuropsychiatric research to worldwide populations. METHODS: We report on T1-weighted structural MRI, resting-state functional MRI, and multi-shell diffusion-weighted imaging of 140 healthy participants (28 per site), two traveling controls, and regular phantom scans. RESULTS: Human image quality measures (IQMs) and outcome measures showed smaller within-site variation than between-site variation. Outcome measures were less variable than IQMs, especially for the traveling controls. Phantom IQMs were stable regarding geometry, SNR, and mean diffusivity, while fMRI fluctuation was more variable between sites. CONCLUSIONS: Variation in IQMs persists, even for an a priori harmonized data acquisition protocol, but after pre-processing they have less of an impact on the outcome measures. Continuous monitoring IQMs per site is valuable to detect potential artifacts and outliers. The inclusion of both cases and healthy participants at each site remains mandatory.

Cell cycle abnormality is a cellular phenotype in OCD.

Abnormal indices of cell cycle regulation have been reported in multiple psychiatric disorders. Though reports specific to Obsessive Compulsive Disorder (OCD) are scant, numerous studies have highlighted partly common underlying biology in psychiatric disorders, cell cycle regulation being one such process. In this study, we therefore aimed to explore cell cycle in OCD. To the best of our knowledge, this is the first study to investigate these effects in OCD. We also evaluated the effect of in vitro fluoxetine, commonly used serotonin reuptake inhibitor (SRI) in OCD patients, on cell cycle regulation. The effects of both disease (OCD) and treatment (SRI) were assessed using lymphoblastoid cell lines (LCLs), derived from OCD patients and healthy controls, as a model system. LCLs were treated with 10µM of fluoxetine for 24 h, and the percentage of cells in each phase of the cell cycle was determined by flow cytometry. We observed a lower proportion of cells in the G2/M phase in OCD cases than controls. The findings suggest that cell cycle dysregulation could be peripheral cellular phenotype for OCD. Among cases, all of whom had been systematically characterized for SRI treatment response, LCLs from non-responders to SRI treatment had a lower proportion of cells in G2/M phase than responders.

Naturalistic outcome of medication-naïve obsessive compulsive disorder treated with serotonin reuptake inhibitors.

OBJECTIVE: The data on the course of obsessive compulsive disorder (OCD) is mostly derived from studying chronic, severely ill patients with varying degree of treatment resistance. We studied the course and outcome of OCD patients who were medication-naïve at initial assessment compared to those who were medicated. MATERIAL AND METHODS: We analyzed the clinical chart data of all patients with a primary diagnosis of OCD attending a speciality OCD clinic in India during a specified period and compared outcome between medication-naïve (n = 75) and medicated (n = 117) patients. RESULTS: The mean time to remission was shorter in the medication-naïve [18.99 months (95 % CI: 14.61-23.37)] compared to medicated [33.91 months (95 % CI: 27.55-40.28)] patients. The survival distribution of the two groups was significantly different as per the log-rank test (χ2 = 5.76, p = 0.02). In the Cox proportional hazards regression, medication-naïve status predicted time to remission. Overall, the rate of remission was the same in both groups (57 %). CONCLUSIONS: Medication-naïve OCD patients seem to remit faster than the previously treated patients. Future prospective naturalistic studies can compare the outcome of medication naïve OCD patients treated with medications and CBT.

Clinical advances in obsessive-compulsive disorder: a position statement by the International College of Obsessive-Compulsive Spectrum Disorders.

In this position statement, developed by The International College of Obsessive-Compulsive Spectrum Disorders, a group of international experts responds to recent developments in the evidence-based management of obsessive-compulsive disorder (OCD). The article presents those selected therapeutic advances judged to be of utmost relevance to the treatment of OCD, based on new and emerging evidence from clinical and translational science. Areas covered include refinement in the methods of clinical assessment, the importance of early intervention based on new staging models and the need to provide sustained well-being involving effective relapse prevention. The relative benefits of psychological, pharmacological and somatic treatments are reviewed and novel treatment strategies for difficult to treat OCD, including neurostimulation, as well as new areas for research such as problematic internet use, novel digital interventions, immunological therapies, pharmacogenetics and novel forms of psychotherapy are discussed.

Long-term Outcomes of Intensive Inpatient Care for Severe, Resistant Obsessive-Compulsive Disorder: Résultats à long terme de soins intensifs à des patients hospitalisés pour un trouble obsessionnel-compulsif grave et résistant.

OBJECTIVE: A substantial proportion of severely ill patients with obsessive-compulsive disorder (OCD) do not respond to serotonin reuptake inhibitors (SRIs) and are unable to practice cognitive behavioral therapy (CBT) on an out-patient basis. We report the short-term (at discharge) and long-term (up to 2 years) outcome of a multimodal inpatient treatment program that included therapist-assisted intensive CBT with adjunctive pharmacotherapy for severely ill OCD patients who are often resistant to SRIs and are either unresponsive or unable to practice outpatient CBT. METHODS: A total of 420 patients, admitted between January 2012 and December 2017 were eligible for the analysis. They were evaluated using the Mini International Neuropsychiatric Interview, the Yale-Brown Obsessive Compulsive Scale (YBOCS), and the Clinical Global Impression (CGI) scale. All patients received 4 to 5 therapist-assisted CBT sessions per week along with standard pharmacotherapy. Naturalistic follow-up information at 3, 6, 12, and 24 months were recorded. RESULTS: At baseline, patients were mostly severely ill (YBOCS = 29.9 ± 4.5) and nonresponsive to ≥2 SRIs (83%). Mean duration of inpatient stay was 42.7 ± 25.3 days. At discharge, there was a significant decline in the mean YBOCS score (29.9 ± 4.5 vs. 18.1 ± 7.7, P < .001, Cohen's d = 1.64); 211/420 (50%) were responders (≥35% YBOCS reduction and CGI-I≤2) and an additional 86/420 (21%) were partial responders (25% to 35% YBOCS reduction and CGI-I≤3). Using latent class growth modeling of the follow-up data, 4 distinct classes were identified, which include "remitters" (14.5%), "responders" (36.5%), "minimal responders" (34.7%), and "nonresponders" (14.6%). Shorter duration of illness, better insight, and lesser contamination/washing symptoms predicted better response in both short- and long-term follow-up. CONCLUSION: Intensive, inpatient-based care for OCD may be an effective option for patients with severe OCD and should be considered routinely in those who do not respond with outpatient treatment.

The prevalence and its correlates of somatization disorder at a quaternary mental health centre.

INTRODUCTION: Somatization Disorder (SD) is known to cause disability and impact the quality of life due to psychological and somatic distress. Though it is a Common Mental Disorder (CMD), the disorder tends to visit all levels of health care, among which prevalence of SD at tertiary care is 10.1%. AIMS: To estimate current prevalence and its correlates of socio-clinical factors in SD at a quaternary mental health centre (QMHC). METHODS: Total of 422 adult subjects were selected through systematic random sampling at first contact psychiatry outpatient clinic. Subjects were interviewed with Mini International Neuropsychiatric Interview Plus version 5.0.0, Clinical Global Impression Severity Scale and Sheehan Disability Scale. RESULTS: Current prevalence of SD was 5%. Significant correlates are observed with median age of 40.5 years, female, married, <5 years of education, monthly income of <₹ 10,357(85.5%) and lower socioeconomic status (75%). DISCUSSION: There is high prevalence of SD even at QMHC. The higher prevalence among adult population in this setup reflect the impairment of working population which invariably impact on national economy. CONCLUSION: Poverty continues to be a major contributing factor to SD causing double impact on the economy by affecting the working population the most.

Neuro-hemodynamic endophenotypes of emotional interference in OCD: fMRI study using emotion counting stroop task.

BACKGROUND: We sought to examine the endophenotype pattern of neuro-hemodynamic substrates of emotion counting Stroop (ecStroop) paradigm in patients with OCD, their unaffected siblings [first degree relatives-FDR] and healthy controls (HC). METHODS: OCD patients (medication naïve)[N = 16], their unaffected siblings(FDR)[N = 16] and HC [N = 24] were compared using an established ecStroop paradigm in a 3-Tesla fMRI. The relative BOLD signals corresponding to the three types of conditions (neural words-N, words with negative emotional salience-E and words with salience for OCD-O) were examined in the apriori hypothesized brain regions. RESULTS: Both in O minus N contrast and O minus E contrast, the groups demonstrated significant differential activation of right insula (BA 13). The post-hoc analyses showed in patients and FDRs relative to HC the following: significant hyperactivation of insula in O minus E contrast; significant hyperactivation of right insula and right DLPFC (BA 9) in O minus N contrast. CONCLUSIONS: The neuro-hemodynamic responses corresponding to the obsessive words in insula and DLPFC could be potential endophenotypes. "Threat relatedness" might thus have a vulnerability meaning in the pathogenesis and neurobiological basis of OCD.

Enhanced error related negativity amplitude in medication-naïve, comorbidity-free obsessive compulsive disorder.

Error monitoring and response inhibition is a key cognitive deficit in obsessive-compulsive disorder (OCD). Frontal midline regions such as the cingulate cortex and pre-supplementary motor area are considered critical brain substrates of this deficit. Electrophysiological equivalent of the above dysfunction is a fronto-central event related potential (ERP) which occurs after an error called the error related negativity (ERN). In this study, we sought to compare the ERN parameters between medication-naïve, comorbidity-free subjects with OCD and healthy controls (HC). Age, sex and handedness matched subjects with medication-naïve, comorbidity-free OCD (N = 16) and Healthy Controls (N = 17) performed a modified version of the flanker task while EEG was acquired for ERN. EEG signals were recorded from the electrodes FCz and Cz. Clinical severity of OCD was assessed using the Yale Brown Obsessive Compulsive Scale. The subjects with OCD had significantly greater ERN amplitude at Cz and FCz. There were no significant correlations between ERN measures and illness severity measures. Overactive performance monitoring as evidenced by enhanced ERN amplitude could be considered as a biomarker for OCD.

Prevalence and correlates of obsessive-compulsive disorder and subthreshold obsessive-compulsive disorder among college students in Kerala, India.

CONTEXT: There are scarce data on the prevalence of adult obsessive-compulsive disorder (OCD) in India. AIMS: The aim was to study the point prevalence of OCD and subthreshold OCD and its psychosocial correlates among college students in the district of Ernakulam, Kerala, India. SETTINGS AND DESIGN: A cross-sectional survey of 5784 students of the age range of 18-25 years from 58 colleges was conducted. MATERIALS AND METHODS: Students were self-administered the OCD subsection of the Clinical Interview Schedule-Revised, the Composite International Diagnostic Interview for obsessive-compulsive symptoms (OCSs), and other relevant instruments to identify OCD, subthreshold OCD, and related clinical measures. STATISTICAL ANALYSIS: The point prevalence of OCD and subthreshold OCD was determined. Categorical variables were compared using Chi-square/Fisher's exact tests as necessary. Differences between means were compared using the ANOVA. RESULTS: The point prevalence of OCD was 3.3% (males = 3.5%; females = 3.2%). 8.5% students (males = 9.9%; females = 7.7%) fulfilled criteria of subthreshold OCD. Taboo thoughts (67.1%) and mental rituals (57.4%) were the most common symptoms in OCD subjects. Compared to those without obsessive-compulsive symptoms (OCSs), those with OCD and subthreshold OCD were more likely to have lifetime tobacco and alcohol use, psychological distress, suicidality, sexual abuse, and higher attention-deficit/hyperactivity disorder symptom scores. Subjects with subthreshold OCD were comparable to those with OCD except that OCD subjects had higher psychological distress scores and academic failures. CONCLUSIONS: OCD and subthreshold OCD are not uncommon in the community, both being associated with significant comorbidity. Hence, it is imperative that both are identified and treated in the community because of associated morbidity.

Cerebellar volume deficits in medication-naïve obsessive compulsive disorder.

Even though conventional neurobiological models of obsessive compulsive disorder (OCD) commonly demonstrate abnormalities involving fronto-striatal circuits, there is emerging evidence regarding the role of posterior brain structures such as cerebellum. In this study, we examined the cerebellar regional volume in a large sample of medication-naïve OCD patients compared to matched healthy controls (HC). In 49 medication naïve right handed OCD patients and 39 age and sex matched HC, sub-region wise volume of cerebellum was extracted from the T1 weighted images using Spatially Unbiased Infra tentorial Template (SUIT) toolbox and compared using hypothesis driven, region of interest approach after clinical assessment with standard scales. After controlling for age, sex and ICV, the subjects with OCD had significantly smaller cerebellum compared to HC, especially in the posterior lobe sub-regions - lobule VI and left crus 1. This study gives preliminary evidence for region specific cerebellar volumetric deficits in the pathophysiological of OCD. Regional cerebellar volume deficits conform to the abnormal connectivity of cerebellum to specific cortical regions and it is indicative of involvement of regions outside the conventional fronto-striatal circuitry. This might be important in the context of cognitive deficits seen in OCD.

Efficacy of mindfulness-integrated cognitive behavior therapy in patients with predominant obsessions.

BACKGROUND: Cognitive behavior therapy (CBT) involving exposure and response prevention is the gold standard psychotherapeutic intervention for obsessive-compulsive disorder (OCD). However, applying traditional CBT techniques to treat patients with predominant obsessions (POs) without covert compulsions is fraught with problems because of inaccessibility of mental compulsions. In this context, we examined the efficacy of mindfulness-integrated CBT (MICBT) in patients with POs without prominent overt compulsions. MATERIALS AND METHODS: Twenty-seven patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of OCD were recruited from the specialty OCD clinic and the behavior therapy services of a tertiary care psychiatric hospital over 14 months. Patients had few or no overt compulsions and were free of medication or on a stable medication regimen for at least 2 months prior to baseline assessment. All patients received 12-16 sessions of MICBT on an outpatient basis. An independent rater (psychiatrist) administered the Yale-Brown Obsessive-Compulsive Scale (YBOCS) and the Clinical Global Impression Scale at baseline, mid- and post-treatment, and at 3-month follow-up. RESULTS: Of the 27 patients, 18 (67%) achieved remission (55% reduction in the YBOCS severity score) at 3-month follow-up. The average mean percentage reduction of obsessive severity at postintervention and 3-month follow-up was 56 (standard deviation [SD] = 23) and 63 (SD = 21), respectively. CONCLUSIONS: Our study demonstrates that MICBT is efficacious in treating patients with POs without prominent overt compulsions. The results of this open-label study are encouraging and suggest that a larger randomized controlled trial examining the effects of MICBT may now be warranted.

Repetitive Transcranial Magnetic Stimulation Over Presupplementary Motor Area May Not Be Helpful in Treatment-Refractory Obsessive-Compulsive Disorder: A Case Series.

BACKGROUND: A significant proportion of patients with obsessive-compulsive disorder (OCD) fail to improve with standard medication and cognitive behavior therapy. Repetitive transcranial magnetic stimulation (rTMS) has been investigated for its role in treating OCD. Low-frequency rTMS over the presupplementary motor area (pre-SMA) has shown mixed results. Moreover, it has not been studied in highly treatment refractory OCD. We analyzed the outcome of low-frequency rTMS over pre-SMA in OCD patients refractory to multiple serotonin reuptake inhibitors (SRIs), augmenting agents, and cognitive behavior therapy. METHODS: Low-frequency (1-Hz stimulus at 100% motor threshold) rTMS was delivered over the pre-SMA using a previously described protocol. At least 25% reduction Yale-Brown Obsessive Compulsive Scale scores and 2-point reduction in Clinical Global Impression-Severity of Illness scores were used to assess treatment response. RESULTS: Seventeen patients were initiated on rTMS. Three of them dropped out within 9 sittings. Only 1 patient met the criteria for response after 1 month of treatment initiation. No major adverse effects were observed in any of them. LIMITATIONS: The study is a retrospective analysis of outcomes when rTMS was administered as part of routine clinical care. Assessments of the patients were done by trained but different raters, and interrater reliability was not measured. CONCLUSIONS: Low-frequency rTMS over the pre-SMA may not be effective in treatment refractory OCD. Further studies, taking note of the possible reasons for ineffectiveness discussed in the study, may help elucidate the role of rTMS in OCD.

A Voxel Based Morphometry Study of Brain Gray Matter Volumes in Juvenile Obsessive Compulsive Disorder.

INTRODUCTION: Adult patients with Obsessive Compulsive Disorder (OCD) have been shown to have gray matter (GM) volume differences from healthy controls in multiple regions - the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), medial frontal gyri (MFG), striatum, thalamus, and superior parietal lobule. However, there is paucity of data with regard to juvenile OCD. Hence, we examined GM volume differences between juvenile OCD patients and matched healthy controls using voxel based morphometry (VBM) with the above apriori regions of interest. METHOD: Fifteen right handed juvenile patients with OCD and age- sex- handedness- matched healthy controls were recruited after administering the Mini International Neuropsychiatric Interview-KID and the Children's Yale-Brown Obsessive Compulsive Scale, and scanned using a 3 Tesla magnetic resonance imaging scanner. VBM methodology was followed. RESULTS: In comparison with healthy controls, patients had significantly smaller GM volumes in left ACC. YBOCS total score (current) showed significant negative correlation with GM volumes in bilateral OFC, and left superior parietal lobule. CONCLUSION: These findings while reiterating the important role of the orbito-fronto-striatal circuitry, also implicate in the parietal lobe - especially the superior parietal lobule as an important structure involved in the pathogenesis of OCD.

INTRODUCTION: Les patients adultes souffrant du trouble obsessionnel-compulsif (TOC) ont révélé des différences de volume de matière grise (MG) d'avec des sujets témoins en santé dans de multiples régions ­ le cortex orbitofrontal (COF), le cortex cingulaire antérieur (CCA), le gyrus frontal moyen (GFM), le striatum, le thalamus, et le lobule pariétal supérieur. Cependant, il y a pénurie de données à l'égard du TOC juvénile. Nous avons donc examiné les différences de volume de MG entre les patients du TOC juvéniles et des sujets témoins appariés en santé à l'aide de la morphométrie voxel à voxel (VBM) dans les régions d'intérêt mentionnées ci-dessus. MÉTHODE: Quinze patients juvéniles droitiers souffrant du TOC et des sujets témoins en santé appariés selon l'âge, le sexe, et la manualité ont été recrutés après l'administration de la Mini International Neuropsychiatric Interview-KID et la Children's Yale-Brown Obsessive Compulsive Scale (YBOCS). Les images ont été obtenues à l'aide d'un scanner d'imagerie de résonance magnétique 3 Tesla, selon la technologie VBM. RÉSULTATS: Comparativement aux témoins en santé, les patients avaient des volumes de MG significativement plus petits dans le CCA gauche. Le score total (actuel) d'YBOCS indiquait une corrélation négative significative avec les volumes de MG dans le COF bilatéral, et le lobule pariétal supérieur gauche. CONCLUSION: Ces résultats réitèrent le rôle important de la circuiterie orbito-fronto-striatale, mais ils impliquent aussi que le lobe pariétal, en particulier le lobule pariétal supérieur, est une importante structure participant à la pathogenèse du TOC.

An epidemological study of obsessive compulsive disorder in adolescents from India.

OBJECTIVES: There is scarce data on the prevalence of OCD among adolescents in India. This study reports point prevalence of OCD among school students (age 12-18years) in the Kerala state of India and examines its association with ADHD, psychological distress, tobacco/alcohol abuse, suicide risk and history of sexual abuse. METHOD: 7560 students of 73 schools were self-administered the OCD subsection of Clinical Interview Schedule-Revised, the Composite International Diagnostic Interview (CIDI) for obsessive compulsive symptoms and other relevant instruments to identify OCD and related clinical measures. A diagnosis of ICD-10 OCD was derived through the CIS-R algorithm which required duration of at least 2weeks and at least a thought/behavior to be resisted along with a cut-off score for severity and impairment. RESULTS: In the sample, 50.3% were males with a mean age of 15.2years (range of 12-18years). The response rate was 97.3% (7380 valid responses). 0.8% (n=61) fulfilled criteria for OCD with a male predominance (1.1 vs. 0.5%, p=0.005). Prevalence was higher among Muslims and increased with age. Taboo thoughts (62.3%) and mental rituals (45.9%) were the commonest symptoms. Those with OCD had significantly higher suicidal thoughts (59 vs. 16.3%, p<0.01) suicide attempts (24.6 vs. 3.8%, p<0.01), ADHD (28 vs. 4%, p<0.001), sexual abuse (24.6 vs. 4.2%, p<0.01), and tobacco use (23 vs. 6.8%, p=0.01). They also reported greater psychological distress and poorer academic performance. CONCLUSIONS: OCD is common among adolescents in India. Its associations with ADHD, sexual abuse, psychological distress, poorer academic performance and suicidal behavior are additional reasons for it to be recognized and treated early.

Prevalence and clinical correlates of obsessive-compulsive disorder in schizophrenia.

Obsessive compulsive symptoms frequently occur in a substantial proportion of patients with schizophrenia. The term schizoobsessive has been proposed to delineate this subgroup of schizophrenia patients who present with obsessive-compulsive symptoms/disorder. However, whether this co-occurrence is more than just co-morbidity and represents a distinct subgroup remains controversial. A striking variation is noted across studies examining prevalence of obsessive-compulsive symptoms/disorder in schizophrenia patients and their impact on clinical profile of schizophrenia. Hence, in this study, we examined the prevalence of obsessive-compulsive symptoms/disorder in a large sample of consecutively hospitalized schizophrenia patients and compared the clinical and functional characteristics of schizophrenia patients with and without obsessive-compulsive symptoms/disorder. We evaluated 200 consecutive subjects with the DSM-IV diagnosis of schizophrenia using the Structured Clinical Interview for DSM-IV Axis I disorders, Positive and Negative Syndrome Scale, Yale-Brown Obsessive-Compulsive Scale, Brown Assessment of Beliefs Scale, Clinical Global Impression-Severity scale, Global Assessment of Functioning Scale, Family Interview for Genetic Studies and World Health Organization Quality of Life scale. The prevalence of obsessive-compulsive symptoms in patients with schizophrenia was 24% (n=48); 37 of them had obsessive-compulsive disorder (OCD) and 11 had obsessive-compulsive symptoms not amounting to a clinical diagnosis of OCD (OCS). Schizophrenia patients with OCS/OCD had an earlier age at onset of schizophrenia symptoms, lower positive symptoms score, higher co-morbidity with Axis II disorders, higher occurrence of OCD in family and better quality of life. Findings of the study indicate a higher prevalence of OCS/OCD in schizophrenia. Schizophrenia patients with and without OCS/OCD have comparable clinical profile with few exceptions. High rates of OCD in first degree relatives suggest possible genetic contributions and differences in neurobiology. Finally, evidence to consider schizoobsessive as a distinct diagnostic entity is inconclusive and warrants further studies.